Technical Field
This application relates to managing multi-step storage management operations.
Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more servers or host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data in the device. In order to facilitate sharing of the data on the device, additional software on the data storage systems may also be used. RAID (Redundant Array of Independent or Inexpensive Disks) parity schemes may be utilized to provide error detection during the transfer and retrieval of data across a storage system (also known as storage arrays or arrays).
In a common implementation, a Storage Area Network (SAN) is used to connect computing devices with a large number of storage devices. Management and modeling programs may be used to manage these complex computing environments.
Storage Management Initiative Specification (SMI-S), and Common Information Model (CIM) technologies, are widely used for managing storage devices and storage environments. CIM is described further below. The SMI-S is a standard management interface that allows different classes of hardware and software products to interoperate for monitoring and controlling resources. For example, the SMI-S permits storage management systems to identify, classify, monitor, and control physical and logical resources in a SAN. The SMI-S is based on CIM, and Web-Based Enterprise Management (WBEM) architecture. CIM is a model for describing management information, and WBEM is an architecture for using Internet technologies to manage systems and networks. The SMI-S uses CIM to define objects that represent storage entities such as Logical Unit Numbers (LUNs), disks, storage subsystems, switches, and hosts. (In many, but not all cases, the term “volume” or “logical volume” is interchangeable with the term “LUN”.) CIM also defines the associations that may or may not exist between these objects, such as a disk being associated to a storage subsystem because it physically resides in the storage subsystem.
The CIM objects mentioned above may be managed by a CIM object manager (CIMOM). A storage management software application can use a CIM client to connect to a CIMOM, to retrieve information about the storage entities that the CIMOM manages, and also to perform active configuration of the storage entities. Storage management software that uses a CIM client may be called a CIM client application.
For example, SMI-S describes how a current storage LUN is mapped. A CIM server is a CIMOM and a set of CIM providers. The SMI-S describes several methods for assigning a LUN from a disk storage system to a host, or for adding a LUN to a disk storage system.
Multiple operations provide a convenient mechanism whereby multiple method invocations may be batched into a single HTTP Message, thereby reducing the number of roundtrips between a CIM client and a CIM server and allowing the CIM server to make internal optimizations. Multiple operations do not confer any transactional capabilities in the processing of the request (for example, there is no requirement that the CIM server guarantee that the constituent method calls either all failed or all succeeded, only that the entity make a “best effort” to process the operation). However, servers process each operation in a batched operation to completion before executing the next operation in the batch.
In general, tasks such as assigning a LUN from a disk storage system to a host, and adding a LUN to a disk storage system, can be complex to execute. Other example tasks may include otherwise allocating storage, specifying the logical and/or physical devices used for the storage allocation, specifying whether the data should be replicated, the particular RAID level, and the like.